| Ibaizabal | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Spain |
| Length: | 43km (27miles) |
| Discharge1 Avg: | 11.8m3/s |
| Basin Size: | 1900km2 |
The Ibaizabal (wide river in Basque) is a river that drains southeastern Biscay to the Estuary of Bilbao. It is 43km (27miles) long from its source at Elorrio to the Nervión, and it passes by the towns of Durango and Amorebieta and joins the Nervión river at Basauri. Both rivers run then together for a short length until they merge with the sea at Bilbao. It is disputed which river is the one that actually reaches Bilbao. It is commonly agreed that it is the Nervión, but there are some who argue that the Ibaizabal carries more water.